This research is directed at understanding the developmental mechanisms which operate to assure functionally appropriate patterns of neuronal connections in the anuran visual system. We are attempting to determine, in particular, whether the synaptic potency of retinal fibers is sufficiently restricted in advance of synapse formation to assure correct connections. We are also analyzing the possible role of visual experience in influencing formation of connections, particularly with respect to the development of binocularity. Neurophysiological, anatomical, and behavioral techniques are being used to compare connectivity in the undisturbed organism with that in organisms subjected to experimental perturbations designed to reveal the operation of particular developmental mechanisms. Among the perturbations currently under study are optic nerve sections, eye rotations and tectal lesions.